After [the passage of the September 2008 tropical storm] Hurricane Ike, the previous owner [of my 1979 MONTAUK 17] struck a submerged log in the Sabine Pass Ship Channel [in Texas]. A large hole was knocked in [the hull on] the port side near the transom. He repaired the hull, and the repair held for many years.
I bought the boat, and all was well until Memorial Day 2024. The hull patch gave way when the boat was on plane. After what sounded like a shotgun blast, I turned and saw a four-foot section of fiberglass fly about ten-feet in the air, leaving the foam interior of the hull exposed. I safely made a 30-minute boat ride back to the launch.
The motto "The Unsinkable Legend" is true.
The inside of the hull was bone dry. But due to not being able to form the fiberglass with no separation in the floatation, the hull is deemed unrepairable, and this old girl is headed to the scrap yard.
Hull Failure Older 17-footer
Re: Hull Failure Older 17-footer
Seeing a photograph of the hull damage after the large section separated would be very interesting.
Q1: where was the damaged area located?
Q1: where was the damaged area located?
Re: Hull Failure Older 17-footer
It's hard to believe the hull is irreparable. Someone who does not understand the value of a used Boston Whaler may believe the hull is uneconomically repairable. As JimH said, a photo would help us understand that conclusion.
Butch
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AggieDad13
- Posts: 4
- Joined: Sat Jul 20, 2024 11:25 pm
Re: Hull Failure Older 17-footer
The problem lies with the fiberglass not being snug to the [embedded foam of the Unibond hull]. A gap is created and when getting on plane, there's a suction created against the surface of the water and the hull. We duck hunt down here and this is why we have tunnel hulled aluminum rigs. The suction created getting on plane is strong. With the gap, the fiberglass started vibrating and the suction created on the surface caused the fiberglass to blow off like a bottle rocket. The cost (without a guarantee of holding) is too much for this old man's pocketbook and peace of mind. I listed it 'as is' in hopes of a BW enthusiast would pick it up, but after four months of it being listed, I had exactly one inquiry. Even at $500 OBO listing price.Scrapping it is hard to fathom but, at this point, I do not have any other option and at least $200 will get me a couple of tanks of gas.
ASIDE: Trying to post pictures [but it is not working] [Check your private messages for advice and help—jimh]
ASIDE: Trying to post pictures [but it is not working] [Check your private messages for advice and help—jimh]
Re: Hull Failure Older 17-footer
Your explanation of how the de-lamination of a large section of the Unibond hull of your 17-foot Boston Whaler occurred sounds very plausible. Once the bond between the laminate and the embedded foam is broken, the hull strength is compromised. The flexing would certain tend to break down the bond of the laminated repair area to the rest of the original laminated layer of the hull.
My inference is the original repair did not provide a strong bond of the repair laminate material to the foam interior. That bond is crucial for a Boston Whaler boat hull to become a unified structure. The actual thickness of the hull laminate is not sufficiently strong without being bonded continuously to the embedded foam.
The lack of a strong bond may be due to the repair being done while the damaged area was still wet. For a proper repair, the foam must be completely dry so a strong bond can be made to it.
Also, the repair may have been made with a laminating resin. Laminating resins are not capable of forming really strong secondary bonds to already cured laminates and foam. The repair should have been made using a resin with much stronger adhesion to secondary bonds. Epoxy resin would be much better for this purpose than a polyester laminating resin or who-know-what was used in the original repair.
My inference is the original repair did not provide a strong bond of the repair laminate material to the foam interior. That bond is crucial for a Boston Whaler boat hull to become a unified structure. The actual thickness of the hull laminate is not sufficiently strong without being bonded continuously to the embedded foam.
The lack of a strong bond may be due to the repair being done while the damaged area was still wet. For a proper repair, the foam must be completely dry so a strong bond can be made to it.
Also, the repair may have been made with a laminating resin. Laminating resins are not capable of forming really strong secondary bonds to already cured laminates and foam. The repair should have been made using a resin with much stronger adhesion to secondary bonds. Epoxy resin would be much better for this purpose than a polyester laminating resin or who-know-what was used in the original repair.
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AggieDad13
- Posts: 4
- Joined: Sat Jul 20, 2024 11:25 pm
Re: Hull Failure Older 17-footer
Two views of the damaged area of the 17-foot hull:
- Fig. 1. Hull damage after original repair was torn away recently while boat was operating on plane.
- hullDamageStarboardSternQuarterAndTransom.jpg (78.85 KiB) Viewed 15027 times
- Fig. 2. Close-up of transom to hull bottom joint showing separation of laminates from foam core and each other.
- hullBottomAtTransomLookingForward.jpg (78.38 KiB) Viewed 15027 times
- Fig. 3. Close-up view of hull damage on bottom, showing torn away laminates and exposed foam. Note the rather thin laminate layer.
- hullBottomDamageCloseUp.jpg (77.27 KiB) Viewed 14969 times
Re: Hull Failure Older 17-footer
From what is shown in Figure 1 there appears to have been a proper grinding and tapering of the original laminate at the joint-line of the repair when the repair was made back in c.2008. You see this in the bluish area that is several inches wide on the perimeter of the repaired area.
The almost rectangular area on the upper transom suggests to me that perhaps there was wood reinforcement there.
Figure 2 shows that the gel coat and underlying laminate where the transom meets the hull bottom has fractured at the bend line. This appears to be new damage to the hull that was not previously repaired. Note the small section of gel coat resin that remains intact shows how the thickness of the gel coat was increased in this concave curve in the mold. Gel coat resin in not particularly strong as a structural bond. The deeper layers of the laminate look like only chopped fibers. Laying up the hull with some woven cloth for this areas would have been a better build option.
The bottom laminate also appears to have separated from the Unibond foam layer.
A proper repair will require adding back missing foam. One way to do that would be to remove more foam to create a uniform depth of missing foam, then glue in place (with strong adhesives) new foam in a series of squares or other shapes cut to fit the necessary area of repair. The new foam should project to just below the prior lines of the hull. Then new fiberglass cloth can be laminated onto the foam. For best adhesion, a marine epoxy resin should be used.
This sort of repair is described in the Boston Whaler instructions for repair of Unibond hulls. See
INSTRUCTIONS--HULL PATCH KITS
https://continuouswave.com/whaler/refer ... tions.html
Read at:
5. Large Structural Repairs (rebuilding of crushed or ripped away sections)
Note the mention of "carved foam block" in the illustration of the repair method as being used below the hull laminate in the damaged area.
Working on this may required flipping the hull over and having the bottom on top. It will be some labor and expense, but for a younger guy with the right skills, it could be done. Exactly how the repair would result cosmetically will be up to the skill of the person making the repair. But it can be done, and the hull integrity should be very good after a proper repair.
The almost rectangular area on the upper transom suggests to me that perhaps there was wood reinforcement there.
Figure 2 shows that the gel coat and underlying laminate where the transom meets the hull bottom has fractured at the bend line. This appears to be new damage to the hull that was not previously repaired. Note the small section of gel coat resin that remains intact shows how the thickness of the gel coat was increased in this concave curve in the mold. Gel coat resin in not particularly strong as a structural bond. The deeper layers of the laminate look like only chopped fibers. Laying up the hull with some woven cloth for this areas would have been a better build option.
The bottom laminate also appears to have separated from the Unibond foam layer.
A proper repair will require adding back missing foam. One way to do that would be to remove more foam to create a uniform depth of missing foam, then glue in place (with strong adhesives) new foam in a series of squares or other shapes cut to fit the necessary area of repair. The new foam should project to just below the prior lines of the hull. Then new fiberglass cloth can be laminated onto the foam. For best adhesion, a marine epoxy resin should be used.
This sort of repair is described in the Boston Whaler instructions for repair of Unibond hulls. See
INSTRUCTIONS--HULL PATCH KITS
https://continuouswave.com/whaler/refer ... tions.html
Read at:
5. Large Structural Repairs (rebuilding of crushed or ripped away sections)
Note the mention of "carved foam block" in the illustration of the repair method as being used below the hull laminate in the damaged area.
Working on this may required flipping the hull over and having the bottom on top. It will be some labor and expense, but for a younger guy with the right skills, it could be done. Exactly how the repair would result cosmetically will be up to the skill of the person making the repair. But it can be done, and the hull integrity should be very good after a proper repair.
Re: Hull Failure Older 17-footer
Anything is possible. The only challenges will be time and money. I would suggest vacuum bagging the epoxy/glass process at first as it will give you the best bond to the foam. I would also suggest some short holes in the foam for epoxy to be pulled into and form a better connection. That is if you are still willing to do the repair.
Re: Hull Failure Older 17-footer
Added third image ( see Figure 3 above) showing close-up of damage to the hull bottom.
Figure 3 shows just how thin the hull laminate layer actually is. What is being seen is that a Boston Whaler boat is really a foam boat with a rather thin layer of laminates moulded around it.
Once there is any separation in the bond between the laminated layer and the interior foam, the laminate layer is no longer really a structural element, as it is too thin to have the necessary stiffness and strength. But that said, these hulls are quite able to last 50-years, as long as the laminate and foam remain bonded.
In theory, when the boat is created in the mold, the innermost layer of the laminate resin is still curing, and the bond between the laminate and foam is a primary bond of two resins curing together with a strong bond between them.
For comparison, below (Figure 4) is a cross section of a Boston Whaler Unibond hull that was on display at a dealer. I think the upper laminate layer is from a section with some embedded reinforcement material; the lower section is probably the hull bottom. I suspect that this hull was rejected during manufacturing for some reason, and then cut up into pieces, some of which were perhaps sent to dealers as possible display objects.
Fig. 4. A cross section cut-out from a Boston Whaler Unibond hull, but the particular model is not known. This was on display at a dealer showroom in 2003.
Figure 3 shows just how thin the hull laminate layer actually is. What is being seen is that a Boston Whaler boat is really a foam boat with a rather thin layer of laminates moulded around it.
Once there is any separation in the bond between the laminated layer and the interior foam, the laminate layer is no longer really a structural element, as it is too thin to have the necessary stiffness and strength. But that said, these hulls are quite able to last 50-years, as long as the laminate and foam remain bonded.
In theory, when the boat is created in the mold, the innermost layer of the laminate resin is still curing, and the bond between the laminate and foam is a primary bond of two resins curing together with a strong bond between them.
For comparison, below (Figure 4) is a cross section of a Boston Whaler Unibond hull that was on display at a dealer. I think the upper laminate layer is from a section with some embedded reinforcement material; the lower section is probably the hull bottom. I suspect that this hull was rejected during manufacturing for some reason, and then cut up into pieces, some of which were perhaps sent to dealers as possible display objects.
Fig. 4. A cross section cut-out from a Boston Whaler Unibond hull, but the particular model is not known. This was on display at a dealer showroom in 2003.
Re: Hull Failure Older 17-footer
I believe the damaged 17-foot hull has found a buyer.